Fix bootstrap problems and various misc issues found along the way

* lisp/simple.el (function-docstring): Fix call to `signal`.

* lisp/emacs-lisp/fcr.el (fcr--define): Use `cl-deftype-satisfies`.

* lisp/emacs-lisp/cl-generic.el (cl--generic-prefill-dispatchers):
Bind `cl--generic-compiler` around the right part of the function (duh!).

lisp/emacs-lisp/cl-generic.el

@@ -880,16 +880,20 @@ those methods.")
     (setq arg-or-context `(&context . ,arg-or-context)))
   (unless (fboundp 'cl--generic-get-dispatcher)
     (require 'cl-generic))
-  (let ((fun (cl--generic-get-dispatcher
-              `(,arg-or-context
-                ,@(apply #'append
-                         (mapcar #'cl-generic-generalizers specializers))
-                ,cl--generic-t-generalizer)))
-        ;; When compiling `cl-generic' during bootstrap, make sure
-        ;; we prefill with compiled dispatchers even though the loaded
-        ;; `cl-generic' is still interpreted.
-        (cl--generic-compiler
-         (if (featurep 'bytecomp) #'byte-compile cl--generic-compiler)))
+  (let ((fun
+         ;; Let-bind cl--generic-dispatchers so we *re*compute the function
+         ;; from scratch, since the one in the cache may be non-compiled!
+         (let ((cl--generic-dispatchers (make-hash-table))
+               ;; When compiling `cl-generic' during bootstrap, make sure
+               ;; we prefill with compiled dispatchers even though the loaded
+               ;; `cl-generic' is still interpreted.
+               (cl--generic-compiler
+                (if (featurep 'bytecomp) #'byte-compile cl--generic-compiler)))
+           (cl--generic-get-dispatcher
+            `(,arg-or-context
+              ,@(apply #'append
+                       (mapcar #'cl-generic-generalizers specializers))
+              ,cl--generic-t-generalizer)))))
     ;; Recompute dispatch at run-time, since the generalizers may be slightly
     ;; different (e.g. byte-compiled rather than interpreted).
     ;; FIXME: There is a risk that the run-time generalizer is not equivalent

lisp/emacs-lisp/fcr.el

@@ -180,11 +180,10 @@
 
 (defun fcr--define (class pred)
   (let* ((name (cl--class-name class))
-         (predname (intern (format "fcr--%s-p" name)))
-         (type `(satisfies ,predname)))
+         (predname (intern (format "fcr--%s-p" name))))
     (setf (cl--find-class name) class)
     (defalias predname pred)
-    (put name 'cl-deftype-handler (lambda () type))))
+    (put name 'cl-deftype-satisfies predname)))
 
 (defmacro fcr-lambda (type fields args &rest body)
   (declare (indent 3) (debug (sexp (&rest (sexp form)) sexp def-body)))

lisp/simple.el

@@ -2343,7 +2343,7 @@ FUNCTION is expected to be a function value rather than, say, a mere symbol."
 	         ;; in the function body, so reject them if they are last.
                  (cdr body))
         doc)))
-   (_ (signal 'invalid-function))))
+   (_ (signal 'invalid-function (list function)))))
 
 (cl-defgeneric interactive-form (cmd)
   "Return the interactive form of CMD or nil if none.